Heart valve replacement may be indicated when there is a narrowing of the native heart valve, commonly referred to as stenosis, or when the native valve leaks or regurgitates, such as when the leaflets are calcified. When replacing the valve, the native valve may be excised and replaced with either a biologic or a mechanical valve.
Conventional heart valve surgery is an open-heart procedure conducted under general anesthesia. An incision is made through the patient's sternum (sternotomy), and the patient's heart is stopped while blood flow is rerouted through a heart-lung “cardiopulmonary” bypass machine. In recent years, advancements in “minimally-invasive” surgery and interventional cardiology have encouraged some investigators to pursue percutaneous replacement of the aortic heart valve. Minimally invasive heart valves are known using expandable stents as anchors for a valve structure. Edwards Lifesciences has developed a balloon-expandable stent integrated with a bioprosthetic valve, which is known as the SAPIENS valve. The stent/valve device is deployed across the native diseased valve to permanently hold the valve open, thereby alleviating a need to excise the native valve. The SAPIEN® device may be delivered in a cardiac catheterization laboratory under local anesthesia using fluoroscopic guidance, thereby avoiding general anesthesia and open-heart surgery.
U.S. Patent Publication No. 2002/0151970 to Garrison et al. describes a two-piece device for replacement of the aortic valve that is adapted for delivery through a patient's aorta. A stent is endovascularly placed across the native valve, then a replacement valve is positioned within the lumen of the stent and connected thereto. By separating the stent and the valve during delivery, a so-called “two-stage” approach, the profile of the delivery system can be reduced. Both the stent and a frame of the replacement valve may be balloon- or self-expandable.
Some researchers propose implanting prosthetic heart valves at the aortic annulus through a ventricular approach. For instance, Christoph H. Huber of the Brigham and Women's Hospital of Harvard Medical School, and others, have proposed a procedure in which a self-expanding valve stent is implanted at the aortic position using a direct-access transapical approach. (E.g., Huber, et al. Direct-access valve replacement a novel approach for off-pump valve implantation using valved stents. J Am Coll Cardiol 2005; 46:366-70). More recently, Bergheim in U.S. Patent Publication No. 2005/0240200 discloses another transapical approach in which either a balloon- or self-expanding valve may be implanted, and also proposes removing or decalcifying stenotic valves. U.S. patent application Ser. No. 11/280,063, filed Nov. 16, 2005, the entire contents of which are expressly incorporated herein by reference, discloses a transapical heart valve delivery system and method, where an expandable prosthetic heart valve is delivered to a desired position via an incision in the apex of the heart.
The selection of the best method for replacing a heart valve is highly dependent upon the condition of a particular patient. For some patients, traditional open heart surgery can be the preferred option. For other patients, such as those who are in extremely frail condition, a minimally-invasive implantation may be desired. It is important for the treating physician to have multiple options for prosthetic heart valve replacement, in order to best serve the needs of a particular patient.
There is a need for additional and improved methods and apparatuses for replacing a heart valve without open-heart surgery or cardiopulmonary bypass. The current invention satisfies this need.